Fingerprint imaging systems apply the known contact method of creating a fingerprint pattern in which a surface topography of a finger is approximated by a series of ridges with intermediate valleys. Conventional full hand image capture devices that capture a full hand image of fingerprints and palm require moving the hand across a cylindrical drum or platen to capture hand and palm ridge formation data. This requires significant operator skill. Furthermore, the technical system employed to capture such images uses a line array sensor which is not suitable for capturing rolled fingerprints. There are palm capture devices that employ a fixed platen prism in combination with a moving line array mechanism. This system requires less operator skill, but captures only a palm image.
Other hand/palm image capture systems exist that employ a cone-shaped hand receiving surface in combination with a moving optical/imager system to form a hand/palm image. However, this system is ergonomically and electronically not capable of scanning rolled fingerprints. Additionally, it is physically very large requiring a cabinet of large dimensions to house the required mechanism and requires substantial operating power to move the mechanism in a controlled fashion and to heat the cone-shaped hand receiving surface to avoid condensation from moist hands.
Systems employing two scanning devices, one for palm and slap fingerprint capture and one for rolled fingerprint capture have been employed; however these are physically large and heavy, and by virtue of the two scanners are expensive to manufacture. Moreover these devices require substantial power to operate, in part due to the need to heat the large prisms to avoid condensation from moist hands.
Systems utilizing a light pipe illumination scheme have been employed. However, the surface illuminated is relatively small and the light pipe structure constructed with a small number of LED light sources applied to the side of the light pipe. To receive the light from the LEDs, the light pipe thickness required in these systems is large, limiting the ergonomic design of the device housing for accommodating finger position beneath the prism illumination face.